Can i Render a specific region in blender with specific resolution?
You can simply use another camera.

Duplicate your camera, and keep it in the same place
Lower the Sensor size to &quot;crop&quot; the image
Use Shift X and Y to &quot;move around&quot;

Because you're not changing focal length, the lens distortion doesn't change.
It's as if you cropped the image in photoshop.